Masked Material settings

Trying to create a simple masked material with a radial blend used as my Opacity mask.(attached) Not quite there yet.
Couple questions
1 Do I need to make any changes to the texture itself in terms of compression, min or max alpha, chroma key texture etc?
2 Does the mask it self need to have an alpha channel?
3 What material settings and blend modes should I be using for the mask to work properly?

Thanks for any feedback!